EXHIBIT 10.41


                       FIRST AMENDMENT TO LEASE AGREEMENT
                       ----------------------------------

        THIS  FIRST  AMENDMENT  ("Amendment")  is  made  as of the  21st  day of
JANUARY,   1999  by  and  between  the  LIBERTY  PROPERTY  LIMITED   PARTNERSHIP
("Landlord"),  successor in interest to Indian Creek Holding  Associates Limited
Partnership, and AMVAX, INC. f/k/a SELCORE LABORATORIES, INC. ("Tenant").

        RECITAL  A.  Landlord  leases to Tenant  approximately  22,800  rentable
square  feet of space in the  building  located  at 12040  Indian  Creek  Court,
Beltsville,  Maryland  (the  "Building")  pursuant  to a Lease  Agreement  dated
December 31, 1987 (the "Lease  Agreement").  The Lease Agreement,  together with
the Rider to Agreement of Lease (the  "Rider") and all other  exhibits  attached
thereto, are collectively referred to herein as the "Lease".

        RECITAL B.  Landlord and Tenant have agreed to amend the Lease under the
terms and conditions set forth herein.

        NOW,  THEREFORE,  for good and valuable  consideration,  the receipt and
sufficiency  of  which is  hereby  acknowledged,  the  parties  hereto  agree as
follows:

        1.  AMENDMENT TO SECTION 2 - TERM.  The "Term" of the Lease,  defined in
Section 2 of the Lease, is hereby extended for an additional  period of 10 years
(the "Extension Period") beyond the Term set forth in the Lease.  Likewise,  the
"Expiration  Date" of the Term of the  Lease,  also  defined in Section 2 of the
Lease,  is hereby  changed to February 28, 2009. In addition,  Sections 2(a) and
(b) of the Lease are hereby deleted and replaced with the following:

            If  Tenant,  or  person  claiming  through  Tenant,  shall
        continue  to  occupy  the  Premises  after the  expiration  or
        termination  of  this  Lease  or  any  renewal  thereof,  such
        occupancy shall be deemed to be under a month-to-month tenancy
        under the same  terms and  conditions  set forth in the Lease,
        except that the  monthly  installment  of Minimum  Rent during
        such continued occupancy shall be double the amount applicable
        to the  last  month  of the  Term.  Anything  to the  contrary
        notwithstanding, any holding over by Tenant without Landlord's
        prior written consent shall constitute a default hereunder and
        shall be subject to all the remedies available to Landlord.

        2.  AMENDMENT TO SECTION 5 - MINIMUM  RENT.  Beginning on March 1, 1999,
and  continuing  during the Extension  Period,  the net component of the minimum
annual  rent under the Lease,  set forth in Section 5 of the Lease,  shall be as
follows:

         Year of                   Annual                Monthly
     Extension Period              Amount              Installment
     ----------------              ------              -----------

     3/1/99 - 2/29/00            $356,986.00           $29,748.83
     3/1/00 - 2/28/01            $367,695.58           $30,641.30
     3/1/01 - 2/28/02            $378,726.45           $31,560.54

   
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     3/1/02 - 2/28/03            $390,088.24           $32,507.35
     3/1/03 - 2/29/04            $401,790.89           $33,482.57
     3/1/04 - 2/28/05            $413,844.61           $34,487.05
     3/1/05 - 2/28/06            $426,259.95           $35,521.66
     3/1/06 - 2/28/07            $439,047.75           $36,587.31
     3/1/07 - 2/29/08            $452,219.18           $37,684.93
     3/1/08 - 2/28/09            $465,785.76           $38,815.48

        Such net component of the Minimum Rent and all additional rent and other
charges  under the  Lease,  shall  continue  to be paid in the manner and at the
times provided in the Lease.




        3.  Sections  2 and 31(g) of the Rider to the Lease are  hereby  deleted
from the Rider and replaced with the following provisions:

            Tenant shall have an option to renew the Term of the Lease
        upon its expiration for an additional  period of 10 years (the
        "Renewal  Term,"  which  shall be  deemed  part of the  Term),
        subject to the following terms:

            (A) In order to exercise this option to renew the Lease, Tenant
   must give  Landlord  written  notice of its  election to renew not later
   than 365 days before the expiration of the then-current  Term. All terms
   of the Lease shall remain in full force and effect for the Renewal Term,
   except that at Landlord's  option, the standard terms of the Lease which
   are not specific to the Tenant's  occupancy  shall be replaced  with the
   Landlord's  then-current  lease  agreement form (with the  understanding
   that the new Rider Section 11 set forth in Paragraph 5 of this Amendment
   below is not one such clause to be replaced), which Tenant shall execute
   within 30 days after receipt thereof, and except that the annual minimum
   rent for the Renewal Term shall be as follows:

         Year of                    Annual                Monthly
     Extension Period               Amount              Installment
     ----------------               ------              -----------

     3/1/09 - 2/29/10             $489,075.05           $40,756.25
     3/1/10 - 2/28/11             $513,528.80           $42,794.07
     3/1/11 - 2/28/12             $539,205.24           $44,933.77
     3/1/12 - 2/28/13             $566,165.50           $47,180.46
     3/1/13 - 2/29/14             $594,473.78           $49,539.48
     3/1/14 - 2/28/15             $624,197.47           $52,016.46
     3/1/15 - 2/28/16             $655,407.34           $54,617.28
     3/1/16 - 2/28/17             $688,177.71           $57,348.14
     3/1/17 - 2/29/18             $722,586.59           $60,215.55
     3/1/18 - 2/28/19             $758,715.95           $63,226.33

            (B) If Tenant  fails to give notice  exercising  the  foregoing
   option by the date required  herein,  or if at the time Tenant exercises
  


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   such  option or at  commencement  of the  Renewal  Term the Tenant is in
   default  of any  term of this  Lease  past  applicable  notice  or grace
   periods,  or if this Lease is assigned by Tenant or the Premises  sublet
   in whole or in part to any party which is not  affiliated  with  Tenant,
   then  Tenant's  right  and  option  to  renew  shall  be   automatically
   terminated and of no further force or effect.

        4.  AMENDMENT  TO SECTION 7 -  INSURANCE.  Section  7(b) of the Lease is
hereby deleted and replaced with the following provision:

            Tenant,   at  its  own  expense,   shall  keep  in  effect
        comprehensive  general liability insurance with respect to the
        Premises and the  Property,  including  contractual  liability
        insurance,  with such limits of  liability  for bodily  injury
        (including  death) and property  damage as  reasonably  may be
        required by Landlord  from  time-to-time,  but not less than a
        combined  single  limit of  $1,000,000  per  occurrence  and a
        general  aggregate  limit of not less than  $3,000,000  (which
        aggregate  limit  shall apply  separately  to each of Tenant's
        locations  if more than the  Premises);  however,  such limits
        shall not limit the liability of Tenant hereunder.  The policy
        of comprehensive general public liability insurance also shall
        name  Landlord and  Landlord's  agent as insured  parties with
        respect to the Premises,  shall be written on an  "occurrence"
        basis and not on a "claims made" basis,  shall provide that it
        shall not be  cancelable  or reduced  without at least 30 days
        prior written notice to Landlord,  and shall be issued in form
        satisfactory  to Landlord.  The insurer shall be a responsible
        insurance  carrier which is authorized to issue such insurance
        and licensed to do business in the state in which the Property
        is located and which has at all times during the Term a rating
        of no less than A VII in the most  current  edition  of Best's
        Insurance  Reports.  Tenant  shall  deliver to  Landlord on or
        before  the  date  on  which  the  Extension   Period  becomes
        effective,  and  subsequently  renewals of, a  certificate  of
        insurance   evidencing   such   coverage  and  the  waiver  of
        subrogation described herein.

        5.  AMENDMENT TO RIDER SECTION 11 - ALTERATIONS BY TENANT. Section 11 of
the Rider to the Lease is hereby  deleted from the Rider and  replaced  with the
following:

            Notwithstanding anything in Section 11 of the Lease to the
        contrary,  in those instances where Tenant is required to seek
        Landlord's   prior  written   approval  for   alterations   or
        improvements   to  the  Premises,   Tenant  shall  deliver  to
        Landlord,  in advance  of any  proposed  construction,  plans,
        specifications,  bid proposals,  work contracts and such other
        information  concerning the nature and cost of the alterations
        or  improvements  as may be reasonably  requested by Landlord.
        Deliveries  to  Landlord  pursuant  to this  section  shall be
        subject to the terms of the written confidentiality  agreement
        dated  December 23, 1997 and  previously  executed by Landlord
        and Tenant if designated  for such  treatment by Tenant at the
        time of delivery to  Landlord.  Landlord  agrees to respond to
        Tenant's  request for approval  within 15 days after receiving
        such  information.  Landlord  acknowledges that the conduct of
        Tenant's  business and the use of the  Premises in  connection
        with   Tenant's   business   are  subject  to  the  rules  and
        regulations of the U.S. Food and Drug Administration and other
        governmental  agencies,  offices,  departments,   bureaus  and
        boards.   Landlord  agrees  that  it  shall  not  unreasonably


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        withhold or  condition  its consent for any such  approvals to
        the extent the same are  reasonably  necessary to cause Tenant
        or the  Premises  to be in  compliance  with all laws,  rules,
        orders, ordinances, directives,  regulations, and requirements
        of all governmental agencies,  offices,  departments,  bureaus
        and  boards   having   jurisdiction   over  the  same  ("Legal
        Requirement").  Nothing in this Lease  shall be  construed  to
        require Tenant to violate any Legal Requirement,  and if it is
        determined  that there are any  additional  restoration  costs
        associated  with any  improvements,  alterations  or additions
        proposed  by  Tenant  as a result  of a Legal  Requirement  or
        otherwise,  then as a condition of Landlord's  approval Tenant
        may be required  to pay  Landlord  as an  additional  security
        deposit an amount equal to the  incremental  demolition  costs
        (if  any)   necessary  as  a  result  of  such   improvements,
        alterations or additions to restore the Premises to a building
        shell condition. In each instance, such incremental demolition
        costs shall be determined  based on estimates of a third party
        contractor mutually acceptable to the parties.

            In addition, and notwithstanding  anything in the Lease to
        the  contrary,  Tenant  shall be  obligated,  at the  Tenant's
        expense  and  prior to the  expiration  of the last day of the
        Term  of  the  Lease,   to  (i)  remove  all  trade  fixtures,
        machinery,  equipment and personal  property  installed at the
        Premises by Tenant,  (ii)  restore the Premises to a so-called
        "building   shell"   condition   as  existing   prior  to  any
        alterations or improvements  made by Tenant,  and (iii) repair
        any damage to the Premises or the building or property  caused
        by such removal and restoration.

        6.  AMENDMENT TO RIDER SECTION 18 -  INDEMNIFICATION.  Section 18 of the
Rider to the  Lease is hereby  deleted  from the  Rider  and  replaced  with the
following:

            (A) Landlord  hereby  indemnifies and holds harmless the Tenant
   from any claims, suits, losses,  damages (but not consequential damages)
   and expenses,  including  attorneys' fees and court costs,  arising from
   any maintenance, repair or other construction work which is performed by
   the Landlord at the Premises  after the receipt by Landlord  from Tenant
   of written notice of the need for such work.

            (B) Tenant shall be  responsible  for insuring,  at replacement
   cost as appropriate, all furniture, equipment, machinery, appliances and
   other  personal  property  owned  by the  Tenant  and  all  alterations,
   fixtures and improvements made by Tenant at the Premises.

        7.  AMENDMENT TO SECTIONS 25 AND 28 - DEFAULTS/REMEDIES. Sections 25 and
28 of the Lease and  Section  28 of the Rider to Lease are  hereby  deleted  and
replaced with the following:

            (A) An "event of default"  shall have occurred  under the Lease
   upon occurrence of any one of the following: (a) the Tenant fails to pay
   any amount of annual minimum or basic rent, additional rent or any other
   sum due  hereunder,  and such  delinquency  continues for a period of 10
   days after written notice from Landlord,  or (b) Tenant fails to perform


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   any of its other duties or obligations,  and such breach continues for a
   period of 30 days after written  notice from Landlord or, if such breach
   cannot be cured within 30 days,  within a reasonable  time not to exceed
   90 days  provided  that tenant  commences to cure such breach  within 30
   days  after  such  notice  and  diligently   prosecutes   such  cure  to
   completion.

            (B) Upon the  occurrence of any event of default,  the Landlord
   may take any or all of the following actions:

               (1)  Perform  on  behalf  of and at the  expense  of  Tenant  any
obligation  of Tenant under this Lease which  Tenant has failed to perform,  the
total cost of which by Landlord,  together with interest  thereon at the rate of
12% per annum from the date of such expenditure, shall be deemed additional rent
and shall be payable by Tenant to Landlord upon demand.

               (2) With or without terminating the Lease,  re-enter the Premises
with or without court action or summary  proceedings and remove all property and
persons  therefrom,  all without  resort to legal  process and without  Landlord
being  deemed  guilty of  trespass  or  becoming  liable  for any loss or damage
occasioned thereby.

               (3) With or  without  terminating  this  Lease,  and from time to
time,  make such  improvements,  alterations  and repairs as may be necessary in
order to relet the  Premises,  and relet the  Premises or any part  thereof upon
such term or terms,  at such  rental or rentals  and upon such  other  terms and
conditions as Landlord in its sole discretion may deem advisable.

               (4) Enforce  any  provision  of the Lease or any other  agreement
between the parties by injunction,  temporary restraining order or other similar
equitable remedy, to which the Tenant hereby expressly consents and agrees.

               (5) Exercise  any other legal or equitable  right or remedy which
it may have by law or otherwise.

            (C) Upon any event of default,  Tenant shall  remain  liable to
   the  Landlord  for  the  following  amounts:  (i) any  rent of any  kind
   whatsoever  which may have become due with  respect to the period in the
   Term which has already  expired,  (ii) all rent which becomes due during
   the remainder of the Term (except that which is actually  collected from
   replacement  tenants,  if any), (iii) all out-of-pocket  costs, fees and
   expenses  incurred by  Landlord  in leasing the  Premises to others from
   time  to  time,  including  but  not  limited  to  leasing  commissions,
   construction and other build-out costs,  design and permitting costs and
   the like, and (iv) all  out-of-pocket  costs, fees and expenses incurred
   by  Landlord in pursuit of its  remedies  hereunder,  including  but not
   limited to attorneys' fees and court costs.  Furthermore,  at Landlord's
   option,  Tenant shall be obligated to pay, in lieu of item (ii) above in
   this paragraph,  an amount (the  "Substitute  Amount") which is equal to
   (a) the  present  value of all rent  which  would  become due during the
   remainder of the Term, including all additional rent, with such present



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   value to be  determined  by  discounting  at an annual  rate of interest
   which is equal to the bond-equivalent  yield for the most recent auction
   of U.S.  Treasury Bills with a 1-year  maturity (the  "Discount  Rate"),
   minus (b) the fair market rental value of the Premises for the remainder
   of the Term,  as  determined  and  calculated  (i) taking  into  account
   vacancy periods for reletting, build-out costs for new tenants and other
   factors,  (ii) by  discounting  to present value at the Discount Rate as
   appropriate,  and  (iii)  by an  independent  real  estate  professional
   selected by  Landlord.  Tenant and Landlord  acknowledge  and agree that
   payment to Landlord of the foregoing  Substitute  Amount is a reasonable
   forecast  of the actual  damages  which will be  suffered by Landlord in
   case of an  event  of  default  by  Tenant,  which  actual  damages  are
   otherwise  difficult or  impossible to  ascertain,  and  therefore  such
   payment and reimbursement together constitute liquidated damages and not
   a penalty. All such amounts shall be payable upon demand by Landlord.

            (D) All  parties  hereto,  both  the  Landlord  and  Tenant  as
   principals  and any  guarantors,  hereby  release  and waive any and all
   rights  provided  by law to a trial by jury in any court or other  legal
   proceeding  initiated to enforce the terms of this Lease,  involving any
   such parties, or connected in any other manner with this Lease.

    (E) Any amount of annual minimum or basic rent, additional rent
   or other sum or charge which is not paid when due  hereunder  shall bear
   interest at an annual rate of 12% from the date due until paid.

        8.  AMENDMENT TO SECTION 32 - NOTICES. Section 32 of the Lease is hereby
deleted in its entirety and the following is substituted in lieu thereof:

            Any notice,  consent,  demand,  bill,  statement  or other
        communication required or permitted to be given hereunder must
        be in writing and may be given by (i) personal delivery,  (ii)
        overnight  courier,  (iii) U.S.  certified or registered  mail
        (and,  if given by mail,  such  notice or other  communication
        shall be deemed  given 2 days  after  being  posted),  or (iv)
        confirmed  facsimile  transmission,  to  the  parties  at  the
        following addresses:

          Landlord:

          Liberty Property Limited Partnership
          c/o Liberty Property Trust
          9145 Guilford Road, Suite 100
          Columbia, MD    21046

          Tenant:

          AMVAX, Inc.
          c/o North American Vaccine, Inc.
          10150 Old Columbia Road
          Columbia, MD    21046


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        Either party may, by notice to the other given  pursuant to this Section
32, specify additional or different addresses for notice purposes.

        9. AMENDMENT TO SECTION 33 - SECURITY DEPOSIT.  Simultaneously  with the
execution and delivery of this Amendment by Tenant to Landlord, Tenant shall pay
to Landlord an amount of  $154,200.00  by  certified  check or wire  transfer of
funds, to be held by Landlord as additional  security  deposit money pursuant to
Section 33 of the Lease.  The parties  hereby agree that such payment,  together
with the $60,800.00  previously  paid by Tenant as a security  deposit under the
Lease (notwithstanding  anything to the contrary in the Lease), shall comprise a
total security  deposit of $215,000.00,  and such amount shall be held,  without
interest,  for the duration of the Term as security for Tenant's  performance of
the Lease.

        10.  APPROVAL  OF  IMPROVEMENTS.  By its  execution  of this  Amendment,
Landlord  approves  the  alterations  to the  Premises  made  by the  Tenant  as
described  in  the  architectural  and  engineering  plans  prepared  by  Quasar
Engineers,  Architects  and  Constructors  (Project  #  94-E-101)  submitted  to
Landlord  under  transmittals  numbered  98-023 (dated  2/13/98),  98-024 (dated
2/20/98) and 98-112 (dated 10/27/98). In addition,  Landlord hereby acknowledges
that, to Landlord's  knowledge  (without  independent  investigation),  provided
Tenant  makes the payment  required by Section 8 of this  Amendment  above,  (i)
Tenant is not in default under the Lease as of the date of this  Amendment,  and
(ii) there exists no occurrence or circumstance which, with the giving of notice
and the passing of time, will become an event of default under the Lease.

        11. SURVIVAL. The Lease will remain in full force and effect, binding on
the parties and unmodified except as expressly set forth in this Amendment. In
the case of any conflicts between the terms of the Lease and the terms of this
Amendment, the terms of this Amendment shall govern.

        IN WITNESS  WHEREOF,  Landlord and Tenant have executed  this  Amendment
intending to be legally bound thereby.


                                Landlord:
                                LIBERTY PROPERTY LIMITED PARTNERSHIP

                                By: Liberty Property Trust, Sole General Partner


Date signed: 1-22-98            By: /s/ Michael C. Weitzmann
                                Name: Michael C. Weitzmann
                                Title: Sr. Vice President



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                                TENANT:
Date signed: January 21, 1999
             ________________             AMVAX, INC.
Witness/Attest:                                



 /s/  Russell P. Wilson         By:  /s/ Lawrence J. Hineline
______________________________      ____________________________________________
Name:  RUSSELL P. WILSON            Name:   LAWRENCE J. HINELINE
Title: ASSISTANT SECRETARY          Title:  VICE PRESIDENT-FINANCE



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